1. if you are infertile, then early or late does not matter

2. either way, the individual "you" does not matter to evolution that works on a population basis (not strictly speaking fully true bc of e.g. bottlenecks, like Mitochondrial Eve, Y-chromosomal Adam, and Genghis Khan, but the idea of "population" can be extended to include such founder effects). i.e. your genetic makeup is determined by millions of years of prior evolution, not what you had for breakfast this morning, so regardless of current fertility status, events such as Alzheimer's are "okay" (again, caveat: purely in the evolutionary sense - though it is horrifying to an individual who gets it) bc they occur post reproductive age, i.e. it is too late bc the genes have already been passed on to another generation.

Insert additional caveats to literally all of this, and also caveats to those caveats, bc biology cares little for how easily it can be understood:-D. e.g. kin selection is also a thing, long past reproductive age and also works for infertile people.